Overexpression of arylsulfatase B or of galactose-6-sulfatase leads to increased expression of syndecan-1 and decorin and increased chondroitin sulfate in MCF-7 cells

2812 Arylsulfatase B (ASB) and galactose-6-sulfatase (GALNS) are human lysosomal enzymes that can modify the glycosaminoglycans (GAGs) chondroitin 4-sulfate (C4S;CSA) and chondroitin 6-sulfate (C6S;CSC), by removing sulfate groups of the target disaccharide at the non-reducing end. This function has clinical significance in the genetic diseases MPS VI and MPS IVA, associated with deficient ASB or GALNS activity, respectively. Previously, we reported that activity of GALNS and ASB in MCF-7 cells is 2-8 fold less than in normal primary mammary epithelial and myoepithelial cells. To determine whether these enzymes may have a role in modification of the GAGs on vital cell surface proteoglycans in malignant cells, we overexpressed these enzymes in MCF-7 cells and determined the impact on expression of syndecan and decorin by QRT-PCR, and on C4S and C6S by Western blot. Since proteoglycans, such as syndecan and decorin, are characterized and differentiated by their GAG side chains, changes in sulfatase function may have relevance for altered cell-cell interactions of malignant cells. MCF-7 cells, grown in phenol-red free RPMI with 10% FBS and Pen-Strep antibiotics, were transiently transfected with full-length ASB (OriGene; NM_000046) or GALNS (Origene; NM_00512.3) in pCMV6-XL4 vector with LipofectamineTM 2000 (Invitrogen). Cell lysate was harvested for RNA extraction or enzyme activity assay at 72 hours. Baseline ASB activity rose from 53.4 (±1.2) to 100.5 (±4.8) nmol/hr/mg protein, an 88% increase. Baseline GALNS activity increased from 3.6 to 8.2 nmol/hr/mg protein, a 228% increase. Quantitative PCR demonstrated 2.2-fold increase in transcript abundance of syndecan-1 and 5.2-fold increase in expression of decorin following overexpression of ASB. Following overexpression of GALNS, there was 3.0-fold increase in syndecan-1 and 2.3-fold increase in decorin transcript expression, compared to control vector transfections. Changes are statistically significant (p